纯镍的高温塑性变形行为及本构方程

发布时间：2018-03-30 13:03

本文选题：纯镍　切入点：热压缩变形　出处：《稀有金属》2015年05期

【摘要】：利用Gleeble-3800热模拟试验机,采用正交实验的方法,进行了单道次压缩试验,研究了纯镍N6板材在不同变形温度和不同应变速率条件下的大变形量热变形行为。结果显示,纯镍N6板坯在大的应变量条件下,出现了稳态流变之后,流变应力再升高的现象;在应变速率一定的条件下,流变应力随变形温度的升高而降低;在相同的变形温度条件下,流变应力随应变速率的增大而增大。说明流变应力与变形温度和应变速率的关系敏感。在变形速率为40 s-1时,流变应力曲线失稳,呈波浪形,说明在较大的应变速率条件下,纯镍N6板材呈现明显的流变失稳特征。并对实验测得的数据进行线性回归,得出双曲正弦函数形式本构方程中的材料参数,将材料参数对应变进行二次拟合,建立了纯镍N6板坯热变形过程中流变应力与变形温度、应变速率及应变的本构关系。经验证,所建立的本构关系能够很好地反应纯镍N6板坯的实际热变形行为特征。
[Abstract]:The single pass compression test was carried out by using Gleeble-3800 thermal simulator and orthogonal test method. The thermal deformation behavior of pure nickel N6 sheet at different deformation temperatures and different strain rates was studied. Under the condition of large strain, the flow stress of pure nickel N6 slab increases after steady state rheology, and the rheological stress decreases with the increase of deformation temperature at a constant strain rate; at the same deformation temperature, the rheological stress increases with the increase of deformation temperature. The rheological stress increases with the increase of strain rate, which indicates that the relationship between rheological stress and deformation temperature and strain rate is sensitive. When the deformation rate is 40 s ~ (-1), the rheological stress curve is unstable, which shows that the flow stress curve is wave-shaped under the condition of large strain rate. The pure nickel N6 sheet shows obvious rheological instability characteristics. The material parameters in the constitutive equation of hyperbolic sinusoidal function are obtained by linear regression of the measured data, and the material parameters are fitted twice to the strain. The constitutive relationship between rheological stress and deformation temperature, strain rate and strain during hot deformation of pure nickel N 6 slab is established. It is proved that the established constitutive relation can well reflect the actual thermal deformation behavior of pure nickel N 6 slab.
【作者单位】：西安建筑科技大学冶金工程学院;
【基金】：陕西省教育厅产业化项目(2011GJ11)资助
【分类号】：TG146.15

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